Method of forming carbureted air mixture



July 24, 1934. c 5 KEGERREIS 1,967,672

METHOD OF FORMING CARBURETED AIR MIXTURE Filed May 51, 1929 gwue'ntow fly 2 (Yazzde S. ifeyerrez's Cuban/art Patented July 24, 7 1934- UNITED STATES PATENT; OFFICE Claude S. Kegerreis, Toledo, Ohio, assignor to The Tillotson Manufacturing Company, Toledo,

Ohio, a corporation of Ohio Application May 31, 1929, Serial No. 367,367

4 Claims.

This invention relates to carbureting devices and embraces a method for supplying a mixture of fuel and air to the cylinders of an internal combustion engine. The usual carburetor consists of a mixing passage in which are located one or more Venturi tubes adapted to cooperate with the main fuel nozzle, the carburetor usually embodying an idling nozzle for use in supplying fuel at low engine speeds. It is a usual custom in carburetor construction to provide so-called air bleeds for the main fuel nozzle for the purpose of admitting air to the fuel at a point anterior of its discharge from the main nozzle so that at comparatively high speeds the mixture will be rendered more lean, i. e., less fuel per a given volume of air will be taken into the cylinders of the engine. The system of leaning or thinning the mixture at high speeds has several disadvantages in that the mixture is sometimes rendered too lean and seriously impairs the operation of the engine, in fact there is too great a tendency to air bleed at high speeds, i. e., too much air is mixed with the liquid fuel before its discharge from the main nozzle.

It is an object of this invention to provide a means whereby the tendency of the mixture to become extremely lean at high speeds is modified to give a more uniform or proper mixture for the engine over the entire range of speed thereof. The invention embraces a fixed arrangement of parts wherein this result is accomplished without the use of complicated adjustable mechanism, thus assuring a positive operation of the device at all times and under all conditions.

The invention further embraces a carburetor of this character incorporating an arrangement of elements whereby a proper fuel mixture ratio is obtained throughout the entire range of operation of the carburetor, and is so constructed that this arrangement of parts cannot be tampered with.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of thereiatecl elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure l is a top plan view of an assembled carburetor embodying my invention;

Figure 2 is a transverse vertical sectional view through the carburetor taken substantially on the line 2-2 of Figure 1.

I have shown the particular arrangement of my invention as incorporated in the carburetor of the so-called plain tube type, but it is to be understood that I contemplate the incorporation of my invention in any structure wherever the same may be found applicable.

Referring to the drawing in detail, the carburetor embodying my invention comprises substantially a mixing passage or chamber 10 communicating with a main air inlet 11 suitably provided with a choke valve 12 of the so-called butterfly type, the mixing chamber 10 having a throttle valve 14 adjacent its outlet. The carburetor is also provided with a. fuel inlet opening connection 16 which has an opening 17 communicating with a fuel chamber or receptacle 18 forming a part of the carburetor. The flow of liquid fuel into the chamber 18 is controlled by means of a vertically movable needle valve 20 connected by means of a lever 21 to a float 22 positioned in the chamber 18. Obviously, the rising fuel in the chamber 18 elevates the float 22 and causes the valve needle 20 to move downwardly cutting off the fiow of fuel when the same reaches a predetermined level.

Positioned in vertical alignment with the axis of the mixing chamber 10 is a fuel nozzle 25 which is connected by means of a passageway 26, chamber 27 and another passageway 28 communicating with the fuel supply in the chamber 18. The passageway 26 is also intercepted by means of a transversely extending passage 30 which connects the tube 26 with a vertical tube or idling well 32. One wall of the mixing passage 10 is provided with a pair of openings leading from a supplemental mixing chamber 36 at the upper extremity of the idling well 32. A threaded member 37 is 1 secured to the body of the carburetor, the inner face of which forms one wall of the supplemental mixing chamber 36, the member 37 being provided with openings 38 leading to the atmosphere, and also an adjusting screw 39 for controlling the flow of air through the openings 38 into the chamber 36. The openings 35 leading into the main. mixing passage 10 substantially adjacent the edge of the throttle 14 are for the purpose of admitting a mixture of fuel and air at lower idling speeds of the engine, 1. e., when the throttle 14 is in closed or substantially closed position as shown in Figure 2.

The main nozzle tube 25 is also in communication with an annular chamber 42 by means of a passageway 43, the annular chamber 42 having an opening 44 to the atmosphere and an opening 45 communicating with the mixing passage 10, and positioned just above the restricted portion of the main venturi 13 forming a part of the mixing passage 10.

The main nozzle 25 projects into the restricted portion of a comparatively small Venturi or choke tube 15, the purpose of the venturis 13 and 15 being to substantially increase the amount and velocity of air acting upon the main nozzle so as to produce additional suction upon the same for the purpose of drawing fuel from the chamber 18 to be mixed with the air in the main mixing passage 10. The transverse passageway 43 is also intercepted by a vertically postioned passage 46 which has an opening 4'7 into the chamber immediately below the main venturi 13.

The operation of the carburetor of my invention is as follows: at slow or idling speeds of the engine with the throttle substantially in the position shown in Figure 2, fuel is taken upwardly through the idling well 32 through the chamber 36 wherein it is mixed with air flowing in through the openings 38, the mixture being then discharged into the mixing passage 10 through openings 35.

This arrangement provides a mixture at low speeds which is substantially uniform. As the throttle 14 is opened and the speed'of the engine increases a corresponding degree, the velocity of the air passing through the mixing chamber 10 taken in through the air inlet 11 is substantially increased and a suction is thereby set up on the main nozzle 25, thus drawing fuel therefrom which is mixed with air in the main and supplemental venturis 13 and 15. Obviously with the fuel at the level shown in Figure 2 in chamber 18, which lever is constantly maintained under the action of the float 22 and the needle valve 20, the fuel normally fills the passageways 26, 30, 43 and 46 up to the point on a level with the height of the fuel in the chamber 18, thus at average engine speeds fuel is being taken from the main nozzle 25 as long as the suction effecting the flow of fuel is not sufliicent to drain the main nozzle at a greater rate than it can be supplied with fuel through the fuel passage 28.

When the suction through the venturis 13 and 15 is sufficient, i. e., at higher engine speeds to drain the fuel from the main nozzle 25 at a rate greater than it can be supplied through the opening 28, the small amount of fuel in the passages 30, 32, 43 and 46 will be taken into the main nozzle and. when the supply of fuel in the tubes 46 and 43 is exhausted, air will be taken into the fuel through openings 44 and 47, this air being mixed with the liquid fuel before it is discharged from the main nozzle 25. This mixing of air with the fuel anterior of its point of discharge from the main nozzle is known as air bleeding. The opening 45 from the annular chamber 42 into the mixing passage 10 is in such a position that the flow of air through the venturi 13 at the ordinary engine speeds produces no appreciable suction upon this opening, and the air bleeding takes place through all three of the openings 44, 45 and 47 to a certain extent. As the speed of the engine greatly increases, the velocity of the air passing through the venturis l3 and 15 is correspondingly increased and because of this increase in velocity of the air through the venturis, a suction is produced on the opening 45 in the venturi 13 where by the direction of flow of air through the opening 45 is reversed and air is drawn into the mixing passage 10 through the opening 45, this air coming from the bleeding openings 44 and 47.

It is apparent that at high speeds a great portion of the air which would be normally introduced through the-pipe 43 into the fuel before it reaches the main nozzle 25, is taken into the mixing passage 10 through the opening 45 and in this manner the degree or amount of air bleeding of the main nozzle is reduced so that more fuel and less air is discharged from the main nozzle. By this means hereinbefore described a richer mixture is introduced into the engine at high speeds which result is accomplished by means of the arrangement of passageways and fixed or metered openings so as to attain the functions as hereinbefore set forth. By this means the engine is enabled to receive the proper quantity of richer fuel mixture at higher speeds coupled with the correct mixture at ordinary speeds, and thus the entire range of operation of the carburetor is greatly improved without the use of any moving parts and no adjustments whatever.

It is apparent that, within the scope of the in- I vention modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What I claim is:

1. The method of forming a carbureted air mixture for an internal combustion engine in which mixture the ratio of liquid fuel and air varies with the speed of the engine comprising moving a column of air past a fuel orifice whereby fuel is discharged into said column of air to form a fuel mixture, and simultaneously admitting air into the fuel before it is discharged into the air column through an air orifice, and at high air velocities of by-passing and discharging into the air column a portion of the air normally admitted into the fuel before it is discharged into the air column whereby at high air velocities the amount of air admitted to the fuel before it is discharged into the air column is proportionately decreased by such by-passing.

2. The method of forming a carbureted air mixture for an interal combustion engine in which mixture the ratio of liquid fuel and air varies with the speed of the engine comprising moving a column of air past a fuel orifice whereby fuel is discharged into said column of air to form a fuel mixture, and simultaneously admitting air into the fuel through an auxiliary air orifice before fuel is discharged into the air column, and at high air velocities of by-passing a portion of the air normally admitted into the fuel before its discharge into the air column around the auxiliary air orifice whereby at high air velocitiesthe amount of air admitted to the fuel before its discharge into the air column is proportionately decreased.

3. The method of forming a carbureted air mixture for an internal combustion engine in which mixture the ratio of liquid fuel and air varies with the speed of the engine comprising: moving a column of air through a restricted zone and past a fuel orifice whereby fuel is discharged into said column of air to form a fuel mixture; of admitting air into the fuel before it is discharged into the air column, and at high air velocities of by-passing a portion of the air normally admitted into the fuel around the restricted zone and fuel orifice and discharging said bypassed air into the air column whereby at high air velocities the amount of air discharged with before its discharge into the air column, and at high air velocities of by-passing a portion of the air normally admitted into the fuel around the fuel orifice and discharging said by-passed air into the air column at the high air velocity passage whereby at high air velocities the amount of air discharged with the fuel into the air column is proportionately decreased.

CLAUDE S. KEGERREIS. 

